This invention relates to a process for removing organic and inorganic contaminants from refinery wastewater streams. More particularly, this invention is directed to a process for removing soluble organic and inorganic contaminants and insoluble organic and inorganic contaminants from refinery wastewater streams employing ultrafiltration and reverse osmosis.
Refinery wastewater streams typically contain many regulated inorganic and organic contaminants that can restrict its use or disposal thereof. Standards promulgated by federal and state agencies that regulate the maximum content of contaminants in wastewater streams disposed into publicly owned treatment works or discharged into waste injection wells have become increasingly more strict. Thus, processes for reducing the content of the inorganic and organic contaminants to an acceptable level in the wastewater streams have been employed to comply with these standards.
For example, U.S. Pat. No. 5,250,185 discloses a method of treating an aqueous charge liquid, e.g., oilfield produced waters, that contains boron and solubilized hydrocarbon compounds to substantially reduce the boron concentration in the liquid. The method involves (1) adding a water softener to the aqueous charge liquid to remove all divalent cations from the liquid; (2) raising the pH of the liquid to above 9.5 and (3) passing the liquid into contact with the high pressure side of a reverse osmosis membrane to recover from the lower pressure side of the membrane the aqueous charged liquid reduced in boron concentration.
Another example is U.S. Pat. No. 5,376,262 which discloses a process to reduce the concentration of inorganic contaminants in a refinery wastewater stream employing reverse osmosis.